IE mode not working for legacy intranet sites in Microsoft Edge

Hi @Davisd ,

Thank you for your question on Microsoft Edge Q&A. I understand your frustration with IE mode not working for legacy intranet sites in Microsoft Edge. Nothing to worry about—I'm here to help you troubleshoot.

Based on your description, here are some likely causes:

• Intranet Zone Mismatch: HTTP-based intranet sites may not trigger IE mode if they're not explicitly added to the Local Intranet Zone or if Group Policy restricts automatic discovery.
• ActiveX Limitations/Blocks: IE mode supports ActiveX, but unsigned controls are often blocked by default security settings, especially after recent updates.
• Site List or Policy Issues: The Enterprise Mode Site List XML might not be deployed correctly, or related policies aren't fully enforced.

I've gathered some targeted solutions—try them in order, starting with Method 1 for quick wins:

Method 1: Verify and Adjust IE Mode Settings for Intranet Sites

• In Edge, go to Settings > Default browser > Allow sites to be reloaded in Internet Explorer mode (ensure it's toggled on).
• Add sites manually if needed: Navigate to edge://settings/defaultBrowser > Under "Internet Explorer compatibility," add your URL and set the compatibility mode to IE11.
• For HTTP intranet sites: Ensure they're trusted—search for Internet Options in the Start menu > Security tab > Local intranet > Sites > Advanced, then add your domain.
  Configure IE mode policies

Method 2: Unblock ActiveX Controls via Internet Properties: (Optional)

• Press Win + R, type inetcpl.cpl, and press Enter.
• Go to Security > Internet (or Local intranet) > Custom level > Scroll to ActiveX controls section > Enable "Run ActiveX controls and plug-ins" and "Script ActiveX controls marked safe for scripting."
• In the Advanced tab, under Security, check "Allow software to run or do something it might not normally be allowed to do on untrusted sites" (for unsigned ActiveX).
• Restart Edge and test your site.

Method 3: Run IE Mode as Admin for Elevated Privileges: (Optional)

• Press Win + R, type "C:\Program Files (x86)\Internet Explorer\iexplore.exe" -Embedding (note: use x86 path if on 64-bit), and run as administrator (right-click > Run as administrator).
• Navigate to your site in this elevated IE instance to bypass potential blocks—if it works, apply the security changes from Method 2 enterprise-wide via Group Policy.

Method 4: Use Enterprise Site Discovery for Better Detection:

• Enable via Group Policy Editor: Computer Configuration > Administrative Templates > Microsoft Edge > Configure Internet Explorer integration (set to Enabled).
• Limit to intranet: Set "Limit Site Discovery output by Zone" to Local Intranet (Zone Mask: 2).
• Run the setup script via PowerShell or Endpoint Manager: powershell.exe -ExecutionPolicy Bypass -File .\IETelemetrySetUp-Win8.ps1 (adapt for Win11 if needed), then restart devices to collect legacy site data and update your Site List.
  Enterprise Site Discovery in Microsoft Edge

I hope these steps resolve the issue! Let's me know if you have any questions.